$\dfrac{7}{10} + \dfrac{4}{8} = {?}$
Answer: ${\dfrac{7}{10}}$ ${\dfrac{4}{8}}$ $+$ ${\dfrac{7 \times 4}{10 \times 4}}$ ${\dfrac{4 \times 5}{8 \times 5}}$ $+$ ${\dfrac{28}{40}}$ ${\dfrac{20}{40}}$ $+$ $ = \dfrac{{28} + {20}}{40} $ $ = \dfrac{48}{40}$